Desulphurization of hydrocarbons



Patented Aug. 19, 1941 UNITED STATES PATENT I OFFICE DESULPHURIZATIQN or nrnaocmons Raphael Rosen, Elizabeth, N. 1., assignor a Standard Catalytic Company Q 6 Claims.

This invention relates to the process of desulphurization of a hydrocarbon containing organically combined sulphur by dehydrogenating organic compounds. It more particularly relates to desulphurization of a petroleum liquid.

According to the process of this invention,

suitable hydrocarbons are dehydrogenated in a desulphurization operation to substantially increase the removal of the organically combined sulphur. It is within the scope of this invention No Drawing. Application May 5, 1937,

, Serial No. 140,836

to increase the efliciency and life of desulphurization catalysts by dehydrogenating organic compounds in the desulphurization operation. The preferred method is to add to a desulphurization operation suitable hydrocarbon compounds which will be dehydrogenated by means of dehydrogenation catalysts under the conditions of temperature and pressure of the operation. The hydrocarbons suitable for dehydrogenation may be added to increase the efficiency of any hydrocarbon desulphurization operation. However, the invention more particularly relates totheir addition to the desulphurization 01' a virgin or cracked liquid petroleum hydrocarbon boiling between 100 F. and 700 F. and containing from 0.1% to 1% sulphur. 1

Any organic compoundcapable of being dehydrogenated under the conditions of the operation employed. However, it is preferred to employ hydroaromatic hydrocarbons and especially stocks containing at least 10% or preferably 20% to 30% or more of hydroaromatic hydrocarbons.

solvent extraction operations are onesource of these complex mixtures in whichselective solvents, as, for instance, liquid sulphur dioxide, acetonitrile, phenyl furfural, ortho anisidine, resorcinol diacetate, ethylene diacetate, tricresyl phosphate,

triphenyl phosphate, aniline, acetone, propane and butane are employed.

If a selective solvent such as liquid sulphur dioxide'is employed to extract a stock containing naphthenic and paraiiin'ic compounds, the desired materials for dehydrogenating are found in the extract. Extraction products from certain stocks naphthenic crudes such as Sugarland or Quiriquire or stocks from crudes containing quantities of naphthenic hydrocarbons such as Conroe, Colombian or West Texas. Another source of preferred material suitable for dehydrogenation is I the raillnate secured by extracting the polymerization product of a thermal polymerization operation. In this operation usually propane and butane are cracked and polymerized at temperatures from 900 to 105021". and at pressures from 1000 to 2000 pounds per square inch. The product of this operation consists essentially of naphthenes and oleflns and by extracting with a suitable solvent, preferably triethylene glycol, capable of selectively dissolvingthe olefin, a desirable rafi'inate high in naphthenic compounds results. The rafllnates or extracts secured by the above methods may be used as such or may be hydrogenated to completely saturate with hydrogen, thereby increasing the hydrogen capable of being released per volume of added material under the conditions of the dehydrogenation operation.

Another source of a mixture containing desirable naphthenic and cyclic compounds is a product secured when destructively hydrogenating petroleum distillates. In this method either a straight run or cracked mineral oil is passed in vapor phase with hydrogen over suitable catalysts at pressures from 20 to 200 atmospheres or higher and at a temperature above 900 F. preferably within the temperature range of930 F. to 1050 F. and the operating conditions and partial pressure of hydrogen so regulated to secure destructive hydrogenation without the formation of appreciable quantities of polymers or coky materials.

It is known that in a desulphurization operation, desulphurization catalysts of the classes of sulphides and oxides of tin, lead, iron, cobalt and molybdenum are eifective. In addition, bauxite is also effective as a catalyst for desulphurization. However, for a certain type of sulphur compounds, particularly when the sulphur is organically combined, and especially when the sulphur is in the ring of the hydrocarbon compound,

thesecatalysts even in the presence of hydrogen are ineflicient and their life is relatively short.

It has been found that if suitable organic compounds as defined above, as, for example naphthenes and hydroaromatic hydrocarbons or mixtures containing these compounds are added to the materials being desulphurized in the presence of catalysts having desulphurization and dehydrogenation properties under conditions to produce dehydrogenation of the added material, the reduction in sulphur will be much greater and the life and activity of the catalyst will be are preferred, as, for instance, stocks from 00 increased.

Any catalyst producing dehydrogenation of the added cyclic or naphthenic compounds is satisfactory; The catalysts employed for desulphurizationlwill also usually be satisfactory as dehydrogenation catalysts under the conditions of the process. If these desulphurization catalysts are not suitable, satisfactory dehydrogenation.catalysts may be added. The preferred catalysts for dehydrogenation are oxides and sulphides of the metals of Group VI of the periodic table and oxides and sulphides. of zinc. aluminum, vanadium and palladium; The salts of these metals treated substantially in a manner as given in Example 1 are also satisfactory. The catalytic .In Test B, it was observed that hydrogen sulphide was evolved which was not observed in- Test A. The above shows that in Test B, in which a substance suitable for dehydrogenation was added, even with a higher volume of liquid per volume of catalyst, the per cent reduction in sulphur was about doubled.

Example 2 A benzine solution containing 0.224%sulphur as thiophene and'25% tetra hydro naphthalene in Test A was passed over a catalyst of lead chrometals may also be satisfactory when contained mate, zinc sulphate and magnesium oxide, while in'the acid radical of a salt, as, for example, chromium in lead chromate. The operation may be carried out under any conditions which produce dehydrogenation of the added materials, as

in Test B a benzine solution containing 0.228%

sulphur as thiophene was passed over an iden-- tical fresh catalyst with the following results:

for instance at temperatures from about 300 to .20 1200 F. However, the preferred conditions are Vl./llq./hr. Tam v per cen temperatures from about 700 F. to 1100 F. or Per "g 3 mlpm higher and at'pressures varying from 12 to 100 pounds per square inch absolute.

T e fo o e p s w l se v to illustrate $3321.11: 1%? 3i$ .fl'f lf ffii 1314 the invention: I

Example! 1 one-half hour at the boiling point of the solution,

then filtered and dried at 572 F. Thedried catalyrt was then treated with 200 cos. of 7 /2% lead acetate solution .forone-half hour at the bcilingpoint of the solution, then filtered, thoroughly washed and dried at 572 F. 75 grams of this lead chromate on burned magnesite was then treated with 150 cos. of zinc sulphate solution at the boiling point of the solution, filtered, first dried at 572 F. and finally at 932 F.

In Test A, the benzine contained 0.311% sulphur and the results as shown are the average The above example shows that with a higher volume of liquid per volume of catalyst, the sulphur reduction secured with the added dehydrogenating compound was over three times the reduction secured when not adding this type of compound. 7

Example 3 of the 7 samples run. In Test B, the benzine VOL/1i Jim I cent solution contained 75% benzine, 25% tetra hyp 9???" Pressure -"h dro naphthalene and 0.465% sulphur, and the results as shown are averages of the four sam- T t A can 3 ples run. Fresh catalysts were used for each zi fi 950-1000 Mmwphem" test.

The temperature and pressure conditions of 65 igifir gifi: 950-1000 the benzine desulphurization operation with reg g fm sults secured were as follows:

VoLIllty/hr. Percent Example 4 pervo .of .,F Pressure sulphur cat. removed V The following data demonstrates clearly the Test A J4 950.1000 Atmosphmo" marked advantage and improvements secured by TestB .97 50-1 0 ----.d -7 the present process over the process of treating with hydrogen gas. I H dr s n Test Reaction {39 nib): mp m'pucent run, Catalyst tempera- Pressure vol. vapor per hours ture, F. my voieg gin Tmed m 8 Mol bdenumsul hide. Atmos heric-- 1-l2 1-1 .214 .107 2: an X p 842 m 1-6 10% tetralln. .mi .160 as r 2,253,808 Thus, from the above it may be seen that-the .32 hours to a short run of three hours during which in this latter case the activity of the catalyst was at a maximum.

The foregoing examples are merely illustrative. Temperatures and pressures and any par-' ticular method of handling maybe varied within the scope of the invention, but the invention is not to be limited byany theory of operation, but

only by the following claims in .which it is desired to claim all novelty insofar as the prior art permits.

I claim: 1

'1. A process of desulphurizing a normally liquid hydrocarbon mixture boiling within the gasoline range and containing organically combined sulphur which comprises adding to said hydrocarbon mixture a hydrocarbon composition containing at least one carbocyclic hydrocarbon wherein two hydrogen atoms are attached to each or at least two nuclear carbon atoms. the carbocyclic hydrocarbon content 01 said hydrocarbon composition amounting to at least passing the resultant hydrocarbon mixture in contact with a dehydrogenation catalyst under dehydrogenat ing conditions at substantially atmospheric pressure and removing the hydrogen sulphide from the reacted mixture, the reaction being carried out in the absence of added free hydrogen.

2. A process which comprises adding tetrahydronaphthalene to a benzine containing organically combined sulphur and contacting the mixture with a dehydrogenation catalyst at the rate 0! about .97 volume of benzine mixture measured as liquid per hour per volume of catalyst at a,

temperature between about 950 and about 1000' F. at substantially atmospheric pressure and re-' moving hydrogen sulphide from the product, the reaction being carried out in the absence 0! added iree hydrogen.

hexane to a cracked petroleum distillate having an initial boiling point oi about 120' E, a final boiling point of about 412' R, an A. P. I. gravity oi. about 52.9, an aniline point or about 103 and containing about 0.98% of organically bound sulphur, contacting said mixture with a'dehydrogenatlon catalyst prepared from lead chromate,

zinc sulphate and magnesium oxide at a thruput of about .143 volume of mixture measured as liquid per hour per volume or dehydrogenation catalyst at a temperature between about 950 and about 1000 F. and removing the sulphur-containing vapors from the product.

4. A process for desulphurization of a petroleum hydrocarbon containing organically combined sulphur comprising adding to a petroleum hydrocarbon boiling between 100 and 700 F. and containing from about .1 to 1% sulphur, at least 10% of a hydroaromatic hydrocarbon, passing the mixture over a dehydrogenation catalyst at a temperature in the range or from about 300 F. to about 1200 F. and under a substantially atmospheric pressure and separating hydrogen sulphide from the resulting products, the reaction being carried out in the absence of added free hydrogen.

5. A process in accordance with claim 4 in which said hydrocarbon is a cracked petroleum distillate containing from about 0.1% to about v 1% sulphur.

drocarbon distillate containing organically coinbined sulphur, com rising adding to a cracked distillate boiling in he range from about to about 700 F. at least 10% of a hydroaromatic concentrate 'secured by solvent extraction of hydrocarbon fractions with suitable extracting agents selected from the class of solvents having a preferential selectivity for the more aromatic type hydrocarbons, passing said mixture in contact with dehydrogenation catalysts at temperatures between about 300 F. and about 1200 F. and under substantially atmospheric pressure and separating the hydrogen sulphide formed, the reaction being carried outin the absence of added free hydrogen.

RAPHAEL ROSEN.

3. A process which comprises adding cycle 

